What is needed is a chrono that can work to the speed of light. It could therefore always check itself against a constant
Seriously though I have never been more surprised by readings than at GP events, its a bit offputting. It seems to me the scan unit is not up to the job. I can see the appeal as they certainly look rugged enough. Why is it that the ever portable combro can be so much more reliable? As long as the batteries are good. Why not ask the combro man to design a unit for events. Providing he can get the parts.